We are requesting funds for an Applied Biosystems (ABI) QSTAR 4000 hybrid linear iontrap/triple quadrupole mass spectrometer system including a nano-electrospray source and a nano-scale high performance liquid chromatograph (nano-HPLC). The proteomics and Metabolomics cores of the UC Davis Genome center (www.genomecenter.ucdavis.edu) are relatively new established entities established to provide proteomic and metabolomic services to researchers on the UC Davis campus. The UC Davis Genome Center proteomics core provides services to two campuses (Sacramento and Davis) which include over 800 biology faculty and more than 4,000 graduate students. There are no additional proteomics or metabolomic service cores on either campus. Currently there is a large demand by NIH funded investigators for analyses that include, complex protein identification, identifying post-translational modifications, such as phosphorylation, and discovery based quantitation including stable label, non-label and multiple reaction monitoring (MRM), analysis of metabolites. The ABI Qtrap 4000 is a state-of-the-art hybrid mass spectrometer that has several unique characteristics that will enable the proteomics and metabolomic cores to target and quantify both peptides and small molecules important to the major users of this proposal. The ABI Qtrap 4000 will have a major impact both on the major users of this grant and the greater UC Davis research community. The ABI Qtrap 4000 will be integrated into our core facilities that will oversee the operation, maintenance and management of this instrument. Relevance The acquisition of an Applied Biosystems Qtrap 4000 will greatly benefit the NIH funded research of the major users listed in this grant. This new mass spectrometer will enable relative and absolute quantitation and specific targeting of post-translational modifications, protein expression metabolites. [unreadable] [unreadable] [unreadable]